Paper stock



Jan. 17, 1939. F. L. BUCHAW ET AL 2,143,840

PAPER STOCK Filed Feb. 5, 1936 4% f g i a K E 5 P 5 M Te h m BS% d V/ 2 FRWM .jlttorneqs Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE PAPER s'roox Minnesota Application February 5, 1936, Serial No. 62,452

3 Claims.

Ourinvention relates to paper stock and particularly to a light caliper paper stock used for forming cartons.

An object of the invention resides in providing a light caliper paper stock which is opaque to the light rays tending to promote rancidity in butter and other fatty substances.

Another object of the invention resides in providing a paper stock which in addition to being opaque to certain light rays has all of the other requirements of paper stock for cartons for butter and other fatty substances.

A still further object of the invention resides in providing a paper stock having the above noted characteristics which will be no thicker than ordinary paper stock used for cartons for such of the body portion or discoloration thereby is prevented or obscured.

Another object of the invention resides in providing a paper stock of the character desired ha ing a liner of a thickness less than that producing opacity to light rays reflected from the coloring of the body portion and passing through the liner and in coloring the liner with a light coloring adapted to obscure such light rays, and preferably a color complementing the color of the commodity contained within the carton.

An object of the invention resides in the method of forming the paper stock.

Other objects of the invention reside in the details of construction hereinafter illustrated and/or described and in the manner of performing and the order of performing the various steps of the method.

In the drawing:

-Fig. 1 is a diagrammatic longitudinal elevational view of a cylinder type of paper making machine.

Fig. 2 is a plan view of a portion of a sheet of paper stock constructed in accordance with our invention and with portions of the same cut away to illustrate the parts of the paper stock.

Fig. 3 is a cross sectional view of the paper shown in Fig. 2 and drawn to an enlarged scale.

This application is ,a continuation in part 01 our application for patent, Serial No. 749,389, filed Oct. 22, 1934 for Paper board.

In practice it has been found that light rays having certain Wave lengths and particularly the shorter wave lengths have the effect of promoting rancidity in butter and other similar fatty substances. Heretofore, wrappers con structed of metal foil, paper and other materials opaque to such light rays have been used in addition to the regular carton in Which the substances are placed for the filtering out of such light rays. adds to the inconvenience of the packer as well as the user. It has been applicants problem to overcome this added expense and inconvenience by providing a paper carton stock which would have in addition to the usual characteristics of such paper stock the added characteristic of filtering out the undesirable light rays. This applicants had to accomplish without appreciably increasing the cost of the stock or without increasing the thickness thereof. Applicants solved the problem by the use of webs of suitable thickness and by the coloring of certain of the webs and by the arrangement thereof, as will hereinafter be more fully described in detail.

For the purpose of illustrating the method of constructing the invention, a portion of an ordinary cylinder type paper making machine has been shown in Fig. 1. This machine comprises a plurality of vats ll, l2, 13, It, l5, l6 and I1 which have cylinders 2|, 22, 23, 2|, 25,26 and 21 placed within the same. These cylinders .are constructed of wire screen of a suitable mesh which i depends upon the kind of fiber used in the stock fed to the-machine. Within these vats are disposed molds 28 which fit about the cylinders and lead the stock to the same. suction-pumps not shown, remove the water from within the cylinders, causing a small hydrostatic head within the various vats which draws the paper stock to the outer surfaces of the cylinders.

overlying each of the cylinders 2| to 21 are a number of couch rolls 29 which occupy the positions relative to said cylinders shown in the drawing. and the various cylinders and picks oil the webs of fibers deposited upon the surfaces of the screen cylinders through the hydrostatic action previously described. The various Webs formed on the cylinders 2|, 22, 23, 24, 25, 26 and 21 are brought together upon the felt 3B andform the composite sheet which is indicated at 32. This sheet adheres to and is carried along with the fell: 30, being disposed upon the underside of This involves additional expense and A number of A. felt 30 passes between the rolls 29 the lower reach 3| of felt 38. The felt 38 is carried back over the last couch roll 29, the upper reach 4| thereof being supported on an upper roll 33. This brings the sheet 32 upon the upper surface of the reach 4| of said felt. A series of tensioning rolls 34, 35, 36 and 31 serve to maintain the proper tension in the felt 38.

Operating in conjunction .with the felt 38 is another felt 38 which has a run 39 which overlies the return run 4| of the felt 38. This felt is supported on rolls 42, 43, 44 and-45 and is maintained in proper tension by means of rolls 46, 41 and 48.

The sheet 32 throughout the runs 39 and 4| of felts 38 and 38 passes between said felts and is run through a series of primary press rolls 5| and 52 which squeeze out a certain percentage of the water. From these rolls the sheet passes through a series of secondary press rolls, the first pair being indicated by the numerals 53 and 54. The felt 38 leaves the sheet 22 when the same passes the last roll 5| and is carried back through the tightener rolls, 46, 41 and 48. This leaves the roll 53 to directly engage the upper surface of the sheet and to give a finish to the same. The sheet 32 after leaving rolls 53 and 54 is successively carried through a second pair of pressrolls 55 and 56, a third pair of press rolls 51 and 58 and through a fourth pair of press rolls 6| and 62.

Operating in conjunction 'with the press rolls 55 and 56 is a felt 63 which is carried on rolls 64 and roll 56 and which comes into line contact- With sheet 22 when in engagement with the roll 55. Tension rolls 65, 66 and 61 are employed for tensioning this felt. In a similar manner another felt 68 corresponding to felt 63 passes over roll 58 and comes into line contact with the sheet 22 when it engages roll 51. Felt 68 passes over rolls 1|, 12, 13 and 14 and is tightened by means of tension rolls 15, 16 and 11. Passing between rolls 6| and 62 is another felt 18 similar to the felt 68. This felt is supported on rolls 8|, 82 and 83 and is tensioned by means of rolls 84, 85 and 86. In the passage of the sheet through the secondary press rolls, one of the rolls of each pair directly engages the sheet so as to give a finish to thesame. It will be noted that the sheet 22 passes through the rolls 51 and 58 in reverse order so that the sheet is finished on both sides thereof. It will further be noted that the first, second and fourth pairs of press rolls finish the sheet on the lowermost surface of the same when the sheet leaves the vats H to I1,

thereby giving a finer finish to this portion ofthe sheet.

The sheet 22 on leaving the press rolls passes through one or more driers 81. These driers consist of heated rolls 88 which are arranged in staggered relation and over which the sheet alternately passes. As many of these driers are utilized as are necessary to properly dry the paper -so that when the paper leaves the machine the same is ready to be cut in sheets or rolled in rolls as required.

Our improved paper stock as shown in Figs. 2

or any other color, or of suitable light absorbing characteristics to exclude or absorb light rays ranging from 7500 Angstrom units through 2408 Angstrom units. A sulphur black aniline dye containing sodium sulphite may be used for the purpose. The thickness of the body 81 varies, depending upon the ultimate thickness of the stock. In a stock of approximately sixteen points thickness, the body 81 would have a thickness of two and one-fourth points.

The facing 88 is preferably white or some other suitable color which is considerably thicker than the body 81. This facing is preferably constructed in two parts designated by the reference numerals 9| and 92. The part 9| is formed entirely of bleached sulphite pulp. The part 92 con-.

sists of approximately seventy-five percent ground wood and twenty-five percent sulphite to receive printing ink. A pulp consisting of fifty percent ground wood and fifty percent sulphite pulp will answer the purpose. In order to maintain the stock the desired thickness it becomes necessary to reduce the thickness of the liner 89 as compared with the thickness of the facing 88. Where the entire thickness of the board is approximately sixteen points, the thickness of the liner would have to be four and three-fourths points. Where a pulp such as specified is used, the coloring from the body 81 would bleed through or the said liner would be sufficiently transparent to show the coloring in the body portion 81 through the same. In order to eliminate this disadvantage a light coloring is used in the liner which obscures or renders invisible any bleeding of or showing of the coloring in the body portion Where the body portion 81 is colored black, a light blue coloring may be used in the liner 89 which produces the desired effect.

The method of forming our improved paper stock on the machine shown in Fig. I is as follows:

The stock used for the liner 89 is placed in the two vats I6 and "and two webs |8I and I82 are formed therefrom by the cylinders 26 and 21 and deposited upon the felt 38. These two webs form in conjunction the liner 89. In the vat I5 is placed the stock forming the body portion 81. A single web I83 is formed from this stock which constitutes the body portion 81. The portion 92 of facing 88 is formed by the two cylinders 23 and 24 and the stock for the same is deposited in the vats I3 and I4. These two cylinders form webs I85 and I86. The portion 9| of the facing 88 is formed by the cylinders 2| and 22 and consists of two webs I81 and I88. The stock for these two webs is placed in the vats II and I2. As the process continues, the various webs are added one to the other and collected on and carried by the lower run 3| of felt 38. The composite sheet of paper formed by the various webs specified passes between the two felts 38 and 38 and through the various primary press rolls, the secondary press rolls and the driers of the paper making machine. When the stock leaves the paper-making machine the same will have been formed with the body portion 81 opaque to the undesirable light rays with the facing 88 opaque to the coloring of the body 81 and the exposed surface thereof suitably finished to receive printing ink and with the liner 89 colored to obscure the coloring of the body 81. After the sheet has been so formed, the same is run through a paraffin machine by means of which a coating I09 is placed upon the inner surface of the liner 89. .If desired, the outer surface of the facing 88 may also be provided with a similar coating of paraifin H0. Where both surfaces of the sheet are paraflined the printing on the sheet is first performed and the parafiining done afterwards. ious fibers of the various webs are interlocked and the resulting sheet is a composite structure of substantially homogeneous character.

Paper stockusedfor cartons for fattysubstances such as butter, lard, oleornargarine and the like, usually run from fourteen to eighteen points in thickness. Where the stock is to be sixteen points, as referred to, the web Ifll would be approximatelytwo and one-half points, and the remaining webs approximately two and onefourth points. It can readily be comprehended, however, that the paper could be made on a machine having less cylinders than that described since thickerwebs can be readily formed than those specified. Also the relative thicknesses of the webs can be varied so long as the ultimate structure has the desired characteristics. An important feature of the invention resides in constructing the facing with a suitable surface for printing and at the same time render the same opaque to light rays reflected from the body portion. This requires a considerable thickness. In order to holddown the ultimate thickness of the paper board, the body portion is made relatively type, size and construction. The particular con-.

struction of the paper stock constitutingv our invention does not affect the flexibility of the stock nor any of the other characteristics which can be procured by the selection of materials suitablefor the purpose.

Our invention is highly advantageous in that our improved paper stock may be used in the customary manner to construct containers for the desired products without involving any particular precaution or change in the method of manufacturing and using such'containers. With our invention the chemical action which causes In the formation of the paper the var-- liner webs fatty substances to become rancid is greatly retarded so that such substances maintain their desiredcondition for a greater length of time than when kept in ordinary containers. Our improved I paper stock can be produced at substantially the same cost as'any other paper stock so that the same can readily be substituted for other types of paper stock now in use for the purpose. Our paper stock can be formed of the same thickness as paper stock now used for the intended purpose and is provided with a facing having a surface suitable for printing the same as ordinary paper stock. By coloring the liner in the manner specified, the bleeding of the die in the body portion or the appearance of the coloring from the same through the liner may be obscured or rendered imperceptible. By the use of a suitable coloring in the liner, a dual function is performed. Where the container is to be used for butter, a blue and preferably a light blue coloring may be used for enhancing the appearance of the butter.

Changes in the specific form of our. invention, as herein disclosed, may be made within the scope of what is claimed without departing from the spirit of our invention.

Having described our invention, what we claim as new and desire to protect by Letters Patent is:

1. A paper stock comprising a facing of surficient thickness and density and having suitable color characteristics to reflect light rays, a body portion of less thickness than said facing, said body portion having a coloring therein serving to cause said body portion to absorb light rays, and a liner of less thickness than said facing capable of reflecting light rays, said liner having sufiicient coloring therein to obscure bleeding through of the coloring in said body portion.

2. A paper stock comprising a facing of a thickness of about nine points, and constructed of a material such as to cause said facing to reflect light rays, a body portion of a thickness of about two and one-quarter points and constructed of a material treated in 'such a. manner as to absorb the light rays tending to promote rancidity in fatty substances, and. a liner constructed of, a material similar to that of said facing and of a thickness of-about me and one-quarter point": and a blue coloring in said liner.

3. A paper stock comprising a body including a web having a dark coloring therein for rendering said web "opaque to the light rays tending to promote rancidity in fatty substances. four facing webs on one side of the body web and jointly forming an opaque facing, two liner webs on the other side of the body web, and similar to the facing web, and forming. a liner of less opacity than said facing, and a light coloring in said obscuring the coloring of said body web.

. FRED L. BUCHANAN.

REYNOLDS GIJYER. 

